Electrical switches



April 30, 1963 P. E. MUELLER ELECTRICAL SWITCHES 2 Sheets-Sheet 1 Filed May 11. 1960 3% ...a v. fi 2 41 W April 30, 1963 P. E. MUELLER ELECTRICAL SWITCHES 2 Sheets-Sheet 2 Filed May 11. 1960 @0404 f finer ii /7 w United States Patent 3,088,004 ELECTRICAL SWITCHES Paul E. Mueller, Milan, Itaiy, assiguor to Bassani S.p.A., Milan, Italy Filed May 11, 1960, Ser. No. 28,256 Claims priority, application Italy May 16, 1959 3 Claims. (Cl. 200-50) This invention relates to electrical switches.

Safety electrical switches having the purpose of impeding any access to internal members of the switch when it is energized are known. These known safety electrical switches include a cap or cover means which is articulated by means of hinges to a cover of the switch, and which serves to cover the fuse-holder caps which are incorporated in the switch. Said cap is held in its closed position by catches which move with the switch lever, and act to permit lifting of the cap only when the switch lever is in the shut-off position. Further safety is provided by elastic plates engaging said catches when the cap is lifted and hindering any movement of the catches and consequently any movement of the switch so that the latter cannot be closed when the cap is lifted.

This invention has the purpose of providing additional safety by permitting the electric connection or disconnection of a load circuit only when the switch is in its off position and the cap is raised.

To this end, the invention comprises first contacting members in the casing of the switch, which contact members are electrically connected to the switch itself, and removable plug means having second contact members which are connected to the load circuit, and which are connectable to said first contact members from the outside of said casing of the switch only when the switch is in its off position, While the removable plug means are disposed, when connected, in a position which is protected by the safety cap when the latter is closed.

Said first contact members are disposed in the interior of the switch casing, underneath its cover and having the form of biased jaws and said removable plug means connected to the load circuit mainly comprises a head member from which the second contact members project substantially normal from one side of said head member insentable between said jaws through openings provided in the switch cover, a tail member of smaller cross section adapted to extend through an aperture in said cap, and a tubular outlet for the passage of electrical conductors which extend preferaby perpendicularly to said second contact members.

A pin, preferably disposed behind the aperture provided in the cap for the outlet of said tail piece, projects from the switch cover, said pin being connected with the neutral member and being grounded, and being arranged to be inserted in a bore of said head, and to project from it to a certain extent in order to present an end arranged to be engaged by a catch provided on the cap.

One example of the present invention is represented in the accompanying drawing, in which:

FIG. 1 is a perspective view of a safety electrical switch according to the invention, and showing the plug means disengaged and the safety cap in its raised position;

FIG. 2 is a perspective View similar to FIG. 1 with the plug means connected and the safety cap in closed position, and

FIG. 3 is a perspective view similar to FIG. 2 and partly cut away.

The fuses 1 of the arrangement are protected by a safety cap or cover means 2 articulated by means of its arms 2 and 2" through hinges on the switch cover 4, in such a manner that it is not possible to displace the switch lever 3 to its on position when said cap is raised since catches 5, which are unitary with the cross piece of said switching lever 3, are secured by springs 6 and thus prevented from moving. On the other hand said cap 2 cannot be raised from its closed position when the lever 3 is in the on position; since when the lever 3 is in this position, the catches 5 are engaged in the stirrups 7' supported by the arms of said cap.

According to this invention there are provided adjacent the fuses 1 connecting or contact means 10 (FIG. 3) having first contact members in the form of springbiased jaws, said connecting sockets being electrically connected to the supply circuit of the switch by means of brackets 37, screws 8, and contacting plates 9. An opening 10' is provided over each socket 10, the openings 10 extending across the switch cover at the bottom of a recess 14 provided in said cover, and presenting an aperture obtained by the interruption of two projections 14 and 14'. The opening 10' are preferably provided in an insulating body.

The sockets are arranged to receive second contact members 11 held by a connecting member or removable plug means 24 connected to a load circuit and including an enlarged head of a shape complementary with the recess 14. Said connecting member 24 is provided with a tail piece 27 which extends between the interrupted ends of the projections 14' and 14. Said tail piece 27 is terminated by a clamping member 29, and a tubular mouth piece 12 for the passage of electrical conductors, both said pieces being disposed with their axes perpendicular to the direction of the second contact members 11. These contact members are preferably flat in order to penetrate more easily the openings 10', which are-of rectangular form.

In said recess 14, between the projections 14 and 14", there is provided a pin v15 which is connected to the neutral elements of the safety switch, and grounded. This pin is designed to be introduced into a bore 28 in the member 24, and to project from the opposite side, and it is provided with a groove 16 for the reception of a catch member supported by the cap 2.

The connecting member 24 is provided with a handle 25 that is articulated on a plate 26 fixed by means of screws to the body 24, said plate presenting an interme diate projection surrounding the bore 28. When the member 24 has been inserted into the recess 14, the handle is disposed as shown in FIG. 3.

As represented in FIGS. 2 and 3, the cap 2 extends simultaneously :over the fuses 11 and the connecting member 24. Said cap is formed with an aperture through which the tail piece 27 extends so that a portion of the latter and the wire clamping member 29 project from said cap when the latter is closed over the inserted connecting member 24.

Cap 2 holds over its front aperture a catch 17 that is constantly urged to a closing position by a spring 23 disposed in :a recess 22 obtained by deformation of the cap. The spring 23 engages with opposite ends an edge of the catch 17 and a supporting member 21 which constitutes a unitary body with the plate 18. Plate 18 covers an upper part of catch .17, and is formed with an intermediate aperture against the border of which a locking means 20 engages, th-at is obtained by an offset portion of said catch '17. Said plate 18 is furthermore provided with a bore 18 through which the end of pin 15 extends when the cap 2 is fully lowered. Pin 15 is formed with a groove 16 into which an edge portion is pressed by the spring 23 when the cap 2 is closed, thus securing the cap in closed position, and also enabling it to be engaged by means of the catches 5 by moving the switch lever 3 to its on position.

In order to raise cap 2 from its closed position, the switch lever 3 has firstly to be moved to its off position, and secondly the hand grip 19 of the catch 17 has to be pressed to release the pin 15. Only when cap 2 is opened will it be possible to reach the connecting member 24, and to disengage it.

Catches 5, as known, ensure that cap 2 cannot be opened before lever 3 has been turned to its off position, and, when opened, they ensure that levers 3 cannot be moved to its on position until the cap: 2 is in position, thus preventing member 24 from being inserted or disengaged when the contacting sockets are energized.

The covering ensured by cap 2, pin 15, and the provision of the contacting sockets underneath the openings 19, further constitute a subsidiary element of safety, since when the cap is lowered to its position of closure and the switch lever 3 is turned to its on position, it will not be easily possible to reach said energized sockets with loose wires or the like.

What I claim is:

1. A safety switch and plug arrangement comprising, in combination, a casing having a front plate being formed with a window and with a plurality of openings spaced from said window; switch means mounted in said casing movable between an on position and an off position and having operating means extending through said window to the exterior of said casing for moving said switch means between said positions thereof; contact means in said casing and electrically connected to said switch means and having a plurality of first contact members respectively aligned with said plurality of openings in said front plate; removable plug means having a plurality of second contact members respectively insertable through said op enings to make electrical contact with said first contact members; cover means hinged to said casing tiltable between a closed position in which said cover means encompasses pant of said plug means to prevent removal thereof and an open position in which said cover means permits withdrawal of said second contact members from said first contact members and therewith removal of said plug means, said cover means being formed with a cutout aligned in said closed position of said cover means with said window permitting operation of said switch operating means in said closed position of said cover means; first manually operable locking means comprising a first member mounted on said casing and a second member mounted on said cover and cooperating with said first member for preventing movement of said cover means from said closed to said open position thereof and one of said members being movable with respect to the other from an engaged to a disengaged position in which said first locking means does not prevent movement of said cover means from said closed to said open position; and second locking means operatively connected to said switch means and being movable from a locking position in which said second locking means engages said cover means to prevent movement of the latter to said open position to an unlocking position only by turning said switch means from said on to said off position thereof.

2. A safety switch and plug arrangement comprising, in combination, a casing having a front plate being formed with a window and with a plurality of openings spaced from said window; switch means mounted in said casing movable between an on position and an off position and having operating means extending through said window to the exterior of said casing for moving said switch means between said positions thereof; contact means in said casing and electrically connected to said switch means and having a plurality of first contact members respectively aligned with said plurality of openings in said front plate; removable plug means comprising a substantially prismatic head member, a plurality of second contact members projecting substantially normal from one side of said head member and being insertable through said openings, respectively, to make electrical contact with said first contact members, and a tail member of a width smaller than that of said head member and extending from the latter from a side thereof substantially normal to said one side, said plug means being formed in said head member thereof with an aperture therethrough extending substantially parallel to said second contact members; cover means hinged to said casing tiltable between a closed position in which said cover means encompasses said head member at all except said one side thereof to prevent removal thereof and an open position in which said cover means permits withdrawal of said second contact members from said first contact members and therewith removal of said plug means, said cover means being formed with a cutout aligned in said closed position of Said cover means with said window permitting operation of said switch operating means in said closed position of said cover means; first manually operable locking means comprising -a pin mounted on said casing and projecting from said front plate substantially normal thereto and being formed in the region of a free end thereof with a notch, a locking member having a locking portion for locking engagement with said notch and being mounted on said cover movable between a locking position in which said locking portion engages in said notch preventing thereby movement of said cover means from said closed to said open position thereof and an unlocking position in which said locking portion is moved out of said notch, and spring means operatively connected to said locking member and tending to keep the same in said locking position thereof; and second locking means openatively connected to said switch means and being movable from a locking position in which said second locking means engages said cover means to prevent movement of the latter to said open position to an unlocking position only by turning said switch means from said on to said off position thereof.

3. A safety switch and plug arrangement comprising, in combination, a casing having a front plate being formed with .a window and with a plurality of openings spaced from said window; switch means mounted in said casing movable between an on position and an off positon and having operating means extending through said window to the exterior of said casing for moving said switch means between said positions thereof; contact means in said casing and electrically connected to said switch means and having a plurality of first contact members respectively aligned with said plurality of openings in said front plate; a plurality of plug fuses mounted on said front plate between said switch means and said openings and electrically connected to said switch means and to said first contact members; removable plug means comprising a substantially prismatic head member, a plurality of second contact members projecting substantially normal from one side of said head member and being insertable through said openings, respectively, to make electrical contact with said first cont-act members, and a tail member of a width smaller than that of said head member and extending from the latter from a side thereof substantially normal to said one side, said plug means being formed in said head member thereof with an aperture therethrough extending substantially parallel to said second contact members; cover means hinged to said casing tiltable between a closed position in which said cover means encompasses said head member at all except said one side thereof to prevent removal thereof and an open position in which said cover means permits withdrawal of said second contact members from said first contact members and therewith removal of said plug means, said cover means being formed with a cutout aligned in said closed position of said cover means with said window permitting operation of said switch operating means in said closed position of said cover means, and said cover means being formed with a plurality of windows having each a cross sectional area smaller than that of said plug fuses and being in the closed position of said cover means respectively aligned with said plug fuses to prevent removal of said fuses while permitting observation thereof; first manually operable locking means comprising a pin mounted on said casing and projecting from said front plate substantially normal thereto and being formed in the region of a free end thereof with a notch, a locking member having a locking portion for locking engagement with said notch and being mounted on said cover movable between a locking position in which said locking portion engages in said notch preventing thereby movement of said cover means from said closed to said open position thereof and an unlocking position in which said locking por- 1 means and being movable from a locking position in 15 which said second locking means engages said cover means to prevent movement of the latter to said open position to an unlocking position only by turning said switch means from said on to said 01f position 5 thereof.

References Cited in the file of this patent UNITED STATES PATENTS 1,798,244 Woodworth Mar. 31, 1931 0 3,018,341 Bassani Jan. 23, 1962 FOREIGN PATENTS 81,211 Switzerland May 16, 1919 130,966 Germany May 1, 1902 

1. A SAFETY SWITCH AND PLUG ARRANGEMENT COMPRISING, IN COMBINATION, A CASING HAVING A FRONT PLATE BEING FORMED WITH A WINDOW AND WITH A PLURALITY OF OPENINGS SPACED FROM SAID WINDOW; SWITCH MEANS MOUNTED IN SAID CASING MOVABLE BETWEEN AN "ON" POSITION AND AN "OFF" POSITION AND HAVING OPERATING MEANS EXTENDING THROUGH SAID WINDOW TO THE EXTERIOR OF SAID CASING FOR MOVING SAID SWITCH MEANS BETWEEN SAID POSITIONS THEREOF; CONTACT MEANS IN SAID CASING AND ELECTRICALLY CONNECTED TO SAID SWITCH MEANS AND HAVING A PLURALITY OF FIRST CONTACT MEMBERS RESPECTIVELY ALIGNED WITH SAID PLURALITY OF OPENINGS IN SAID FRONT PLATE; REMOVABLE PLUG MEANS HAVING A PLURALITY OF SECOND CONTACT MEMBERS RESPECTIVELY INSERTABLE THROUGH SAID OPENINGS TO MAKE ELECTRICAL CONTACT WITH SAID FIRST CONTACT MEMBERS; COVER MEANS HINGED TO SAID CASING TILTABLE BETWEEN A CLOSED POSITION IN WHICH SAID COVER MEANS ENCOMPASSES PART OF SAID PLUG MEANS TO PREVENT REMOVAL THEREOF AND AN OPEN POSITION IN WHICH SAID COVER MEANS PERMITS WITHDRAWAL OF SAID SECOND CONTACT MEMBERS FROM SAID FIRST CONTACT MEMBERS AND THEREWITH REMOVAL OF SAID PLUG MEANS, SAID COVER MEANS BEING FORMED WITH A CUTOUT ALIGNED IN SAID CLOSED POSITION OF SAID COVER MEANS WITH SAID WINDOW PERMITTING OPERATION OF SAID SWITCH OPERATING MEANS IN SAID CLOSED POSITION OF SAID COVER MEANS; FIRST MANUALLY OPERABLE LOCKING MEANS COMPRISING A FIRST MEMBER MOUNTED ON SAID CASING AND A SECOND MEMBER MOUNTED ON SAID COVER AND COOPERATING WITH SAID FIRST MEMBER FOR PREVENTING MOVEMENT OF SAID COVER MEANS FROM SAID CLOSED TO SAID OPEN POSITION THEREOF AND ONE OF SAID MEMBERS BEING MOVABLE WITH RESPECT TO THE OTHER FROM AN ENGAGED TO A DISENGAGED POSITION IN WHICH SAID FIRST LOCKING MEANS DOES NOT PREVENT MOVEMENT OF SAID COVER MEANS FROM SAID CLOSED TO SAID OPEN POSITION; AND SECOND LOCKING MEANS OPERATIVELY CONNECTED TO SAID SWITCH MEANS AND BEING MOVABLE FROM A LOCKING POSITION IN WHICH SAID SECOND LOCKING MEANS ENGAGES SAID COVER MEANS TO PREVENT MOVEMENT OF THE LATTER TO SAID OPEN POSITION TO AN UNLOCKING POSITION ONLY BY TURNING SAID SWITCH MEANS FROM SAID "ON" TO SAID "OFF" POSITION THEREOF. 